Vehicle or truck restraints are frequently associated with a loading dock to prevent accidental movement of a truck away from a loading dock while a loading operation is in progress and the conventional truck restraint is designed to engage the ICC bar which is a horizontal bar or beam located beneath the rear end of the truck bed.
Various forms of truck restraints have been proposed. In certain truck restraints, a hook-like restraining member is pivoted in a vertical plane between a lower storage position and an upper operative position where it will engage the ICC bar and prevent movement of the truck away from the dock, while other truck restraints utilize a linear moving hook that is moved vertically between a lower storage position and an upper operative position.
If a truck attempts to pull away from the loading dock while the truck restraint is in the operative position, a substantial force is exerted by the truck against the restraining hook. To withstand this outward force, the truck restraint is designed with substantial size and weight which results in considerable frictional resistance to movement of the hook. Because of the frictional resistance, a substantial actuation force is required to move the hook between the storage and operative positions.
A truck restraint must also incorporate a provision to accommodate float of the truck bed during a loading operation. As cargo or material handling equipment, such as a fork-lift truck, is moved onto the truck bed, the truck bed will depress against the force of the truck suspension. Conversely, as cargo is removed from the truck bed, the truck bed will rise. The truck restraint must be able to accommodate this float to maintain the restraining member or hook in engagement with the truck at all times during the loading operation. With a conventional truck restraint which has substantial size and weight, relatively large spring forces are required to provide the floating action.
While all trucks are required to have an ICC bar to prevent underriding of an automobile in the event of a rear end collision, the fore and aft location, as well as the vertical height, of the ICC bar may vary from truck to truck. It is important that a truck restraint be capable of handling both extreme high and low ICC bars in order to have universal usage.